1. Field of the Invention
The present invention relates to an absorption refrigerating/heating apparatus or airconditioner and particularly, an absorption refrigerating/heating apparatus for heating at high efficiency with a heat pump in an ordinary heating mode and, when the outside air temperature is too low to pump up heat, shifting to a direct flame heating mode to maintain the heating capacity to a desired level as well as permitting simple switchover between the refrigerating mode, the thermodynamic heating mode, and the direct flame heating mode.
Also, the present invention is directed towards an absorption refrigerating/heating apparatus which improves the start of shifting from the direct flame heating mode to the thermodynamic heating mode.
2. Description of the Related Art
As absorption type refrigerating apparatuses have commonly been used for only refrigerating, they are now arranged for not only refrigerating action but also carrying out a thermodynamic heating action in which heat pumped up by the absorber is used for heating. In such a thermodynamic heating action, however, the efficiency of pumping up heat from the outside air is declined when the temperature of the outside air drops. A modification is provided for shifting from the thermodynamic heating action to the direct flame heating mode when the outside air temperature drops to some lower limit.
Disclosed in Japanese Patent Publication Nos. Hei 1-47714 and Hei 7-96977 and Japanese Patent Laid-open Publication No. Hei 6-2980 are such a modified absorption heat-pump apparatus and a refrigerating/heating apparatus. An absorption refrigerating/heating apparatus which performs in any of three modes; refrigerating, thermodynamic heating, and direct flame heating is depicted in Japanese Patent Publication No. Hei 6-97127.
Those conventional absorption refrigerating/heating apparatuses of air-cooling type are complicated in the construction where switching is needed from refrigerating mode to heating mode and vice versa and will thus hardly be feasible in practice.
For example, to shift between the refrigerating mode and the thermodynamic heating mode in the apparatus disclosed in the Patent Publication No. Hei 6-97127, the passage for a refrigerant or an absorbent solution has to be switched. This causes undesired mixture of the absorbent solution with the refrigerant. For implementation, therefore, the switching between the three modes of cooling, thermodynamic heating, and direct flame heating can only be realized with the use of intricate mechanisms. Although the apparatus disclosed in the Patent Publication No. Hei 1-47714 employs four-way valves for switching between the refrigerating mode and the heating mode to form a simplified passage switching mechanism, the switching between the refrigerant passage and the absorbent solution passage is inevitable. Accordingly, the mixture of the refrigerant with the absorbent solution will occur hence requiring a length of time to return back to an expected level of performance after the switching.